Protective device for the sealing of a stern tube of propeller-driven ships

ABSTRACT

A protective device for a stern tube seal of a propeller-driven vessel, wherein an intermediate space is left open between a stern tube and a propeller hub, which intermediate space is covered by a tubular protective cover concentric with the propeller hub, which protective cover is fixedly anchored to the stern tube and axially overlies the propeller hub leaving an annular gap, wherein a ring concentric with the propeller hub and U-shaped in radial section is disposed inside the protective cover in the intermediate space between the stern tube and the propeller hub, the U-opening of which ring is directed radially outward, and wherein the ring is at least partially formed of a material that has a pourable consistency at 20° C.

The invention relates to a protective device for the stern tube seal ofpropeller-driven vessels, wherein an intermediate space is left openbetween the stern tube and the propeller hub, which intermediate spaceis covered by a tubular protective cover (rope guard) concentric withthe propeller hub, which protective cover is on the one hand fixedlyanchored to the stern tube and on the other hand spreads over thepropeller hub leaving an annular gap, wherein a ring concentric with thepropeller hub and configured U-shaped in radial section is disposedinside the protective cover in the intermediate space between stern tubeand propeller hub, the U-opening of which ring is directed radiallyoutward.

A protective device of the above-described type is known from DE 37 18419 C2. According to this, a net guard is installed on vessels forprotection of the stern tube-seal and -bearing. This net guard isusually flange-mounted directly on the drive propeller. Should nets andropes be located in the water, they are wound up due to the U-shapedgeometry of the guard and received in the U-shaped design until amaintenance, in the context of which a removing of the nets and ropes iseffected.

Here the ring is disposed and dimensioned in relation to the annular gapsuch that ends of fishing lines, fishing nets, or similar cord-shapedstructures possibly entering through the annular gap are captured by itand wound up.

Due to the large diameter of the ring in question, of the material used(aluminum bronze is usually used for this purpose), of the manufacturingmethod, and of the processing, relatively high costs arise thatsometimes induce the operators of vessels to omit the net guard. Inaddition there is the high weight that complicates the handling,installation, and maintenance of the rings. Of course the omission ofthe net guard, i.e., of said ring, represents a great danger to thevessel propulsion.

To attach the rope guard, i.e., the ring, using screws, a hole patternis required in the ring for flange mounting, which hole pattern variesdepending on the vessel or on the respective application. Thereforedepending on the application case the bores are introduced shortlybefore the delivery or installation of the net guard.

The object of the invention is to further develop a protective device ofthe above-described type for the stern tube seal of propeller-drivenvessels such that the disadvantages mentioned are avoided. Accordinglyan easily handleable and cost-effective solution is to be provided. Boththe manufacture of the net guard and its installation should thus beable to be simplified.

The solution of this object by the invention is characterized in thatthe ring is at least partially comprised of a material that can have apourable consistency at room temperature (T=20° C.). Concrete, inparticular mineral casting, is preferably considered here.

Here the ring is preferably comprised of at least two ring sectors,wherein each ring sector extends over a defined circumferential angleand wherein the ring sectors are preferably connected to one another.Particularly preferably two, three, four, five, or six ring sectors areprovided here that form the ring.

Here the ring sectors can be oriented relative to one another usingcentering elements; the centering elements are preferably formed from acomplementary profiling of the end regions of the ring sectors, whichend regions lie in the circumferential direction.

The ring or the ring sectors are preferably attached to the propellerhub or to the protective cover using a screw connection. It is thenadvantageous here if insert parts are disposed in the ring sectors,which insert parts are penetrated by at least one screw. The insertparts here are preferably at least partially surrounded by the materialof the ring.

The material is preferably comprised of filler materials and binder andoptionally of additives, wherein the filler material preferably has aweight proportion between 80% and 95%, wherein the binder preferably hasa weight proportion between 5% and 20%, and wherein the binder ispreferably comprised of a resin, in particular of epoxy resin, and ahardener, in particular of an aminic hardener. All components of thematerial together have 100 weight-%.

Furthermore it can be provided that reinforcing fibers are added to thematerial, in particular glass fibers, carbon fibers, or metallic fibers.

As mentioned reinforcing fibers can be added to the ring. In addition tothe fibers mentioned these are also understood to include steel bars,meshes, reinforcing iron, cages, steel mesh, and similar elements, suchas are also used with normal concrete. A mesh can also be incorporatedinto the material.

Concrete is a mixture of cement, aggregate, and mixing water; concreteadditives and concrete admixtures are also optionally included. Thecement acts as a binder to hold together the other components. Thestrength of the concrete is produced by crystallization of the clinkerparticles of the cement under water absorption.

Fibers made from steel, plastic, carbon, or glass can be added to theconcrete in order to obtain fiber concrete.

In contrast to normal concrete, mineral casting (also called polymerconcrete) contains a polymer, i.e., a plastic material, as binder, thatholds together the aggregate. Cement is used in mineral casting, if atall, only as filler and assumes no binding effect. The most widely usedpolymer matrix for mineral casting is unsaturated polymer resin.

In its area of application mineral concrete has significantly bettermechanical and chemical properties than cement-concrete. The settingtime of these resins can be set by the amount of catalysts and hardenersused. Epoxy resin is preferably used as polymer, i.e., as binder, inorder to generate a good vibration-damping behavior.

In general all materials can be used for the implementation of theproposed idea that can be cast “cold,” i.e., materials that can have apourable consistency at room temperature (20° C.).

The invention thus provides an effective net guard for a vessel drive,in particular made from mineral casting. Here the ring can be one-partor segmented. Various separation geometries can be realized with sectors(or segments) in order to facilitate the exact connecting of sectorsinto a complete ring; however, the exact connection is of no greatimportance for the function.

The bores for attaching the rings or the sectors of the rings can becast together during manufacturing. Inlay parts (inlays) made fromvarious materials (for example, from stainless steel, from brass, frombronze, from aluminum, from fiberglass, from carbon-fiber-reinforcedplastic, or from plastic) can also be used here. The inlays can bedesigned differently, serve for force transmission from the screws, andprevent the spalling of the mineral casting. In addition, further inlayscan be cast together, for example, threaded-bushings and -bolts.

In order to take into account varying bore patterns and in order tocover this to the extent possible with only one mold, there are thefollowing approaches:

Firstly slot-inlays have proven successful. These inlays can be providedstraight, or curved kidney-shaped (i.e., with or without a radius in thecircumferential direction). They are introduced in the mineral castingand can in particular be cast.

Inlays can also be configured as solid-material inlays. In this casethey are manufactured from solid material (e.g., bronze, brass,stainless steel, plastic); they are cast together during casting of thering or of the ring sectors. The hole pattern can then be directlyintroduced into the solid-material inlay, after removal of the ring orof the ring sector from the mold, according to customer specificationsby drilling. Such inlays here must have an appropriate geometry in orderto be securely anchored in the mineral casting.

Eccentric inlays are also possible. A bore is eccentrically introducedinto this inlay; the inlay can be constructed in the manner of a slidingbearing. By turning a part of the inlay the position of the bore can bechanged and thus adapted to the required connection geometry.

Mineral casting has only approximately one quarter of the density ofaluminum bronze (which is 8.6 g/cm³). A significant weight reduction andthus advantages with the handling and the installation of the ring or ofits sectors thereby result. Combined with the segmenting the handling-and installation-advantages increase. Manual installation is nowpossible. This saves the use of cranes, lifting- and assembly-tools andreduces the time consumption.

The variety of variants for the end user is maintained, but issignificantly reduced for the manufacturer of the rings. By introducingthe above-mentioned inlays it is possible to work with only one mold andnevertheless replicate the complete range of different hole patterns.The results are cost- and time-savings.

Thus a significant cost advantage results from the use of mineralcasting instead of the material aluminum bronze used to date.

Exemplary embodiments of the invention are depicted in the drawings.

FIG. 1 shows in radial section a protective device for the stern tubeseal of a vessel drive including a net guard in the shape of a ring,

FIG. 2 shows in radial section the ring (net guard) according to a firstembodiment of the invention,

FIG. 3 shows in radial section and in front view the ring according toFIG. 2,

FIG. 4 shows in radial section the ring according to a furtherembodiment of the invention,

FIG. 5 shows in radial section the ring according to a furtherembodiment of the invention,

FIG. 6 shows in front view a ring sector that is a component of the ringaccording to a further embodiment of the invention,

FIG. 7 shows in front view four ring sectors according to FIG. 6, thattogether form the ring,

FIG. 8a , FIG. 8b , and FIG. 8c show as viewed from a radial perspectivethe joint of two adjacent ring sectors shortly before their meeting at acircumferential point of the ring,

FIG. 9 shows in radial section the ring according to a furtherembodiment of the invention,

FIG. 10 shows in radial section the ring according to a furtherembodiment of the invention,

FIG. 11 shows in front view the ring, wherein an inlay part is depicted,

FIG. 12 shows in front view the ring, wherein two slots for theattaching are depicted, and

FIG. 13 shows in front view the ring, wherein an eccentric insert forthe attaching is depicted.

In FIG. 1 a stern tube seal 1 can be seen that is embodied as amulti-lip seal and includes a plurality of seal lips 13, which interactwith a bush 14 that is mounted on a propeller shaft 15. The bush 14 isconnected by one end via a flange 16 to the propeller hub 3 andprotrudes by the other end into the stern tube 2.

The intermediate space 17 thereby formed is covered by a tubularprotective cover 4, which on the one hand is fixedly attached to thestern tube 2 and a piece of which on the other hand projects over thepropeller hub 3 leaving an annular gap 5.

A ring 6, U-shaped and concentric with the propeller hub 3, is disposedin the intermediate space 17 formed by the protective cover 4, whichring 6 is open radially outward, i.e., toward the protective cover 4,and is attached to the end side of the propeller hub 3 using an onlyschematically indicated screw connection 8. The dimensions of the ring 6are selected such that in its receiving space formed by the U-shapedstructure a plurality of winding layers of ends of fishing lines,fishing nets, etc. possibly penetrated into the annular gap 5 can bereceived. The stern tube seal 1 is thereby protected.

For details explicit reference is made to the above-mentioned DE 37 18419 C2.

It is essential that according to the invention the ring 6 is at leastpartially comprised of a material B that can have a pourable consistencyat room temperature (T=20° C.). Mineral casting is considered here inparticular.

In FIG. 2 the radial section of the ring 6 can be seen. From this itfollows that bores 10 are introduced in the ring 6 in order to be ableto attach the ring 6 to the propeller hub 3 using screws 8. For thepurpose of assembly a mounting bore 18 flush with the bore 10 isavailable that is provided for the passage of an appropriate tool.

It follows from FIG. 3 that the ring 6 can be configured as a one-piecepart.

Insert parts 9, preferably made from metal, can be introduced into thebores or inserted into the mold during casting of the ring 6 in order toensure stable support for the attaching of the ring 6. In particular aspalling of material of the ring 6 can thus be avoided. FIGS. 4 and 5here show two different solutions.

In FIGS. 6 and 7 it can be seen that the ring 6 can also be comprised ofa plurality of sectors 6′, 6″, 6′″, and 6″″, which each cover acircumferential section.

In order that the individual sectors accurately abut on one another inthe circumferential direction and are accurately positioned in the axialdirection a (see FIG. 1), centering elements 7 can be provided as areshown in FIGS. 8a, 8b, and 8c for three different variants. Accordinglythe precise axial assembly of the ring sectors 6′, 6″ can be improved bythe measures depicted here.

Here the transition region between two ring sectors 6′, 6″ is depicted,wherein the view from the radial direction is outlined. As can be seenfrom the three views according to FIGS. 8a, 8b, and 8c , the joints arenot configured flat, but rather crosswise or angled (see FIG. 8a ) or inthe manner of an arrow design (see FIG. 8b and FIG. 8c ). The last twopossibilities mentioned ensure the precise axial assembly of the twoabutting ring sectors 6′ and 6″ so that with the assembling of the ringsectors the individual parts are arranged precisely with respect to eachother.

A better installability thus results, in particular with only twosegments or sectors. Furthermore, there is a simple possibility of acentering of the sectors relative to one another.

In FIG. 9 an insert part 9 is outlined again that has been cast togetherwith the casting of the ring 6 or of its sectors. In FIG. 10 it can beseen how said insert part 9 has then been pierced in order to be able toattach the ring 6 according to a desired hole pattern.

For this purpose it can be seen in FIG. 11 that an insert part 9 can beprovided that includes different bores and thus makes possible thescrewing-on of the ring 6 in the context of a certain variability.

The variability is increased more if—as can be seen in FIG. 12—slots 11are provided that are configured kidney-shaped here and thus make itpossible that the ring 6 can be fixedly screwed in a simpler manner

For this purpose FIG. 13 shows a still further possibility: here aninsert part is provided in the form of an eccentric insert 12. Thisinsert is formed in the manner of a sliding bearing and has two ringsthat can be rotated relative to each other (see arrow in FIG. 13). Byturning the inner ring of the eccentric insert 12 the position of thepassage bore for the screw can thus be changed and adapted to a threadedbore in the propeller hub.

REFERENCE NUMBER LIST

1 Stern tube seal

2 Stern tube

3 Propeller hub

4 Protective cover (rope guard)

5 Annular gap

6 Ring

6′ Ring sector

6″ Ring sector

6′″ Ring sector

6″″ Ring sector

7 Centering element

8 Screw connection

9 Insert part

10 Bore

11 Slot

12 Eccentric insert

13 Seal lip

14 Bush

15 Propeller shaft

16 Flange

17 Intermediate space

18 Mounting bore

B Material (mineral casting/polymer concrete)

a Axial direction

1. A protective device for a stern tube seal of a propeller-drivenvessel, wherein an intermediate space is left open between a stern tubeand a propeller hub, which intermediate space is covered by a tubularprotective cover concentric with the propeller hub, which protectivecover is fixedly anchored to the stern tube and axially overlies thepropeller hub leaving an annular gap, wherein a ring concentric with thepropeller hub and configured U-shaped in radial section is disposedinside the protective cover in the intermediate space between the sterntube and the propeller hub, the U-opening of which ring is directedradially outward, and wherein the ring comprises a material that has apourable consistency at 20° C.
 2. The protective device according toclaim 1, wherein the material is concrete.
 3. The protective deviceaccording to claim 1 wherein the ring is comprised of at least two ringsectors, wherein each ring sector extends over a defined circumferentialangle and wherein the ring sectors are connected to one another.
 4. Theprotective device according to claim 3, wherein two, three, four, five,or six ring sectors form the ring.
 5. The protective device according toclaim 3 wherein the ring sectors are aligned relative to one another bycentering elements, and wherein the centering elements are formed from acomplementary profiling of end regions of the ring sectors lying in acircumferential direction.
 6. The protective device according to claim1, wherein the ring or the ring sectors is or are attached to thepropeller hub or to the protective cover using a screw connection. 7.The protective device according to claim 6, wherein insert parts aredisposed in the ring or in the ring sectors, which insert parts arepenetrated by at least one screw.
 8. The protective device according toclaim 7, wherein the insert parts are at least partially surrounded bythe material of the ring.
 9. The protective device according to claim 1,wherein the material is comprised of filling materials and binder,wherein the filling material has a weight proportion between 80% and95%, wherein the binder preferably has a weight proportion between 5%and 20%, and wherein the binder is comprised of a resin and a hardener.10. The protective device according to claim 1, wherein glass and/orcarbon and/or metallic reinforcing fibers are present in the material.11. The protective device according to claim 1, wherein the material ismineral casting.
 12. The protective device according to claim 9, whereinthe resin is an epoxy resin and wherein the hardener is an aminichardener.
 13. The protective device according to claim 2, wherein thering comprises at least two ring sectors, wherein each ring sectorextends over a defined circumferential angle and wherein the ringsectors are connected to one another, wherein the ring sectors arealigned relative to one another by centering elements, and wherein thecentering elements are formed from a complementary profiling of endregions of the ring sectors lying in a circumferential direction,wherein the ring or the ring sectors is or are attached to the propellerhub or to the protective cover using a screw connection, wherein insertparts are disposed in the ring or in the ring sectors, which insertparts are penetrated by at least one screw and are at least partiallysurrounded by the material of the ring, wherein the material iscomprised of filling materials and binder, wherein the filling materialhas a weight proportion between 80% and 95%, wherein the binder has aweight proportion between 5% and 20%, and wherein the binder iscomprised of a resin and a hardener, and wherein reinforcing fibers arepresent in the material.
 14. A protective device for protecting a sterntube seal of a propeller-driven vessel, the protective device beingmountable in an intermediate space between a stern tube and a propellerhub inside a protective cover adjacent an annular gap between thepropeller hub and the protective cover, the protective devicecomprising: a ring concentric with the propeller hub and having anoutwardly facing channel with an outwardly facing opening, the ringbeing formed at least partially of a material that is pourable at 20° C.15. The protective device according to claim 14, wherein the ringcomprises concrete.
 16. The protective device according to claim 14,wherein the ring comprises mineral casting.
 17. The protective deviceaccording to claim 14, wherein the ring comprises at least two ringsectors, each ring sector extending over a defined circumferentialangle.
 18. The protective device according to claim 14, wherein the ringsectors are aligned relative to one another by a complementary profilingof circumferential end regions of the ring sectors.